Rework MediaQueryMatcher to batch up listener notification

Source/core/css/MediaQueryList.h

Index: Source/core/css/MediaQueryList.h
diff --git a/Source/core/css/MediaQueryList.h b/Source/core/css/MediaQueryList.h
index ba04100cc723e42cb75d7e957d579b52408ff66d..a05beee3d07b40367b60f00347f0c9361237ab68 100644
--- a/Source/core/css/MediaQueryList.h
+++ b/Source/core/css/MediaQueryList.h
@@ -38,27 +38,32 @@ class MediaQuerySet;
 // will be called whenever the value of the query changes.
 
 class MediaQueryList FINAL : public RefCountedWillBeGarbageCollected<MediaQueryList> {

[Mads Ager (chromium), 2014/06/26 06:06:22]

Since the class now has a non-trivial destructor it needs to be
...WillBeGarbageCollectedFinalized. (The plugin will complaint about this if you
compile with enable_oilpan=1, so this will be easy for us to catch and fix when
you land.)

[cbiesinger, 2014/06/26 20:27:59]

Done.

-    DECLARE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(MediaQueryList);
 public:
-    static PassRefPtrWillBeRawPtr<MediaQueryList> create(PassRefPtrWillBeRawPtr<MediaQueryMatcher>, PassRefPtrWillBeRawPtr<MediaQuerySet>, bool);
+    static PassRefPtrWillBeRawPtr<MediaQueryList> create(PassRefPtrWillBeRawPtr<MediaQueryMatcher>, PassRefPtrWillBeRawPtr<MediaQuerySet>);
+    virtual ~MediaQueryList();
+
     String media() const;
     bool matches();
 
     void addListener(PassRefPtrWillBeRawPtr<MediaQueryListListener>);
     void removeListener(PassRefPtrWillBeRawPtr<MediaQueryListListener>);
 
-    bool evaluate(MediaQueryEvaluator*);
+    void mediaFeaturesChanged(WillBeHeapVector<RefPtrWillBeMember<MediaQueryListListener> >* toNotify);
 
     void trace(Visitor*);
 
+    void documentDetached();
+
 private:
-    MediaQueryList(PassRefPtrWillBeRawPtr<MediaQueryMatcher>, PassRefPtrWillBeRawPtr<MediaQuerySet>, bool matches);
-    void setMatches(bool);
+    MediaQueryList(PassRefPtrWillBeRawPtr<MediaQueryMatcher>, PassRefPtrWillBeRawPtr<MediaQuerySet>);
+
+    bool updateMatches();
 
     RefPtrWillBeMember<MediaQueryMatcher> m_matcher;
     RefPtrWillBeMember<MediaQuerySet> m_media;
-    unsigned m_evaluationRound; // Indicates if the query has been evaluated after the last style selector change.
-    unsigned m_changeRound; // Used to know if the query has changed in the last style selector change.
+    typedef HeapListHashSet<RefPtrWillBePersistent<MediaQueryListListener> > ListenerList;

[esprehn, 2014/06/26 05:43:24]

I think this should be a Member, you only need to use Persistent when you're
storing things in a container off the Oilpan heap.

[Mads Ager (chromium), 2014/06/26 06:06:22]

MediaQueryList, MediaQueryListListener and HeapListHashSet are all on the oilpan
heap and pointers between them should be Members. Therefore, this should be
RefPtrWillBeMember. Also, you might want to use WillBeHeapListHashSet to only
use a heap allocated collection when oilpan is enabled.

[cbiesinger, 2014/06/26 20:27:59]

Done.

+    ListenerList m_listeners;
+    bool m_matchesDirty;
     bool m_matches;
 };